1
2
3
4#include <linux/kernel.h>
5#include <linux/module.h>
6#include <linux/bio.h>
7#include <linux/blkdev.h>
8
9#include "blk.h"
10
11
12
13
14
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16
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18
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20
21
22
23
24int blk_queue_ordered(struct request_queue *q, unsigned ordered,
25 prepare_flush_fn *prepare_flush_fn)
26{
27 if (!prepare_flush_fn && (ordered & (QUEUE_ORDERED_DO_PREFLUSH |
28 QUEUE_ORDERED_DO_POSTFLUSH))) {
29 printk(KERN_ERR "%s: prepare_flush_fn required\n", __func__);
30 return -EINVAL;
31 }
32
33 if (ordered != QUEUE_ORDERED_NONE &&
34 ordered != QUEUE_ORDERED_DRAIN &&
35 ordered != QUEUE_ORDERED_DRAIN_FLUSH &&
36 ordered != QUEUE_ORDERED_DRAIN_FUA &&
37 ordered != QUEUE_ORDERED_TAG &&
38 ordered != QUEUE_ORDERED_TAG_FLUSH &&
39 ordered != QUEUE_ORDERED_TAG_FUA) {
40 printk(KERN_ERR "blk_queue_ordered: bad value %d\n", ordered);
41 return -EINVAL;
42 }
43
44 q->ordered = ordered;
45 q->next_ordered = ordered;
46 q->prepare_flush_fn = prepare_flush_fn;
47
48 return 0;
49}
50EXPORT_SYMBOL(blk_queue_ordered);
51
52
53
54
55unsigned blk_ordered_cur_seq(struct request_queue *q)
56{
57 if (!q->ordseq)
58 return 0;
59 return 1 << ffz(q->ordseq);
60}
61
62unsigned blk_ordered_req_seq(struct request *rq)
63{
64 struct request_queue *q = rq->q;
65
66 BUG_ON(q->ordseq == 0);
67
68 if (rq == &q->pre_flush_rq)
69 return QUEUE_ORDSEQ_PREFLUSH;
70 if (rq == &q->bar_rq)
71 return QUEUE_ORDSEQ_BAR;
72 if (rq == &q->post_flush_rq)
73 return QUEUE_ORDSEQ_POSTFLUSH;
74
75
76
77
78
79
80
81 if (!blk_fs_request(rq))
82 return QUEUE_ORDSEQ_DRAIN;
83
84 if ((rq->cmd_flags & REQ_ORDERED_COLOR) ==
85 (q->orig_bar_rq->cmd_flags & REQ_ORDERED_COLOR))
86 return QUEUE_ORDSEQ_DRAIN;
87 else
88 return QUEUE_ORDSEQ_DONE;
89}
90
91bool blk_ordered_complete_seq(struct request_queue *q, unsigned seq, int error)
92{
93 struct request *rq;
94
95 if (error && !q->orderr)
96 q->orderr = error;
97
98 BUG_ON(q->ordseq & seq);
99 q->ordseq |= seq;
100
101 if (blk_ordered_cur_seq(q) != QUEUE_ORDSEQ_DONE)
102 return false;
103
104
105
106
107 q->ordseq = 0;
108 rq = q->orig_bar_rq;
109 __blk_end_request_all(rq, q->orderr);
110 return true;
111}
112
113static void pre_flush_end_io(struct request *rq, int error)
114{
115 elv_completed_request(rq->q, rq);
116 blk_ordered_complete_seq(rq->q, QUEUE_ORDSEQ_PREFLUSH, error);
117}
118
119static void bar_end_io(struct request *rq, int error)
120{
121 elv_completed_request(rq->q, rq);
122 blk_ordered_complete_seq(rq->q, QUEUE_ORDSEQ_BAR, error);
123}
124
125static void post_flush_end_io(struct request *rq, int error)
126{
127 elv_completed_request(rq->q, rq);
128 blk_ordered_complete_seq(rq->q, QUEUE_ORDSEQ_POSTFLUSH, error);
129}
130
131static void queue_flush(struct request_queue *q, unsigned which)
132{
133 struct request *rq;
134 rq_end_io_fn *end_io;
135
136 if (which == QUEUE_ORDERED_DO_PREFLUSH) {
137 rq = &q->pre_flush_rq;
138 end_io = pre_flush_end_io;
139 } else {
140 rq = &q->post_flush_rq;
141 end_io = post_flush_end_io;
142 }
143
144 blk_rq_init(q, rq);
145 rq->cmd_flags = REQ_HARDBARRIER;
146 rq->rq_disk = q->bar_rq.rq_disk;
147 rq->end_io = end_io;
148 q->prepare_flush_fn(q, rq);
149
150 elv_insert(q, rq, ELEVATOR_INSERT_FRONT);
151}
152
153static inline bool start_ordered(struct request_queue *q, struct request **rqp)
154{
155 struct request *rq = *rqp;
156 unsigned skip = 0;
157
158 q->orderr = 0;
159 q->ordered = q->next_ordered;
160 q->ordseq |= QUEUE_ORDSEQ_STARTED;
161
162
163
164
165
166 if (!blk_rq_sectors(rq)) {
167 q->ordered &= ~(QUEUE_ORDERED_DO_BAR |
168 QUEUE_ORDERED_DO_POSTFLUSH);
169
170
171
172
173
174
175 if ((q->ordered & QUEUE_ORDERED_BY_TAG) &&
176 !(q->ordered & QUEUE_ORDERED_DO_PREFLUSH)) {
177 q->ordered &= ~QUEUE_ORDERED_BY_TAG;
178 q->ordered |= QUEUE_ORDERED_BY_DRAIN;
179 }
180 }
181
182
183 blk_dequeue_request(rq);
184 q->orig_bar_rq = rq;
185 rq = NULL;
186
187
188
189
190
191
192
193 if (q->ordered & QUEUE_ORDERED_DO_POSTFLUSH) {
194 queue_flush(q, QUEUE_ORDERED_DO_POSTFLUSH);
195 rq = &q->post_flush_rq;
196 } else
197 skip |= QUEUE_ORDSEQ_POSTFLUSH;
198
199 if (q->ordered & QUEUE_ORDERED_DO_BAR) {
200 rq = &q->bar_rq;
201
202
203 blk_rq_init(q, rq);
204 if (bio_data_dir(q->orig_bar_rq->bio) == WRITE)
205 rq->cmd_flags |= REQ_RW;
206 if (q->ordered & QUEUE_ORDERED_DO_FUA)
207 rq->cmd_flags |= REQ_FUA;
208 init_request_from_bio(rq, q->orig_bar_rq->bio);
209 rq->end_io = bar_end_io;
210
211 elv_insert(q, rq, ELEVATOR_INSERT_FRONT);
212 } else
213 skip |= QUEUE_ORDSEQ_BAR;
214
215 if (q->ordered & QUEUE_ORDERED_DO_PREFLUSH) {
216 queue_flush(q, QUEUE_ORDERED_DO_PREFLUSH);
217 rq = &q->pre_flush_rq;
218 } else
219 skip |= QUEUE_ORDSEQ_PREFLUSH;
220
221 if ((q->ordered & QUEUE_ORDERED_BY_DRAIN) && queue_in_flight(q))
222 rq = NULL;
223 else
224 skip |= QUEUE_ORDSEQ_DRAIN;
225
226 *rqp = rq;
227
228
229
230
231
232 return !blk_ordered_complete_seq(q, skip, 0);
233}
234
235bool blk_do_ordered(struct request_queue *q, struct request **rqp)
236{
237 struct request *rq = *rqp;
238 const int is_barrier = blk_fs_request(rq) && blk_barrier_rq(rq);
239
240 if (!q->ordseq) {
241 if (!is_barrier)
242 return true;
243
244 if (q->next_ordered != QUEUE_ORDERED_NONE)
245 return start_ordered(q, rqp);
246 else {
247
248
249
250
251 blk_dequeue_request(rq);
252 __blk_end_request_all(rq, -EOPNOTSUPP);
253 *rqp = NULL;
254 return false;
255 }
256 }
257
258
259
260
261
262
263 if (!blk_fs_request(rq) &&
264 rq != &q->pre_flush_rq && rq != &q->post_flush_rq)
265 return true;
266
267 if (q->ordered & QUEUE_ORDERED_BY_TAG) {
268
269 if (is_barrier && rq != &q->bar_rq)
270 *rqp = NULL;
271 } else {
272
273 WARN_ON(blk_ordered_req_seq(rq) < blk_ordered_cur_seq(q));
274 if (blk_ordered_req_seq(rq) > blk_ordered_cur_seq(q))
275 *rqp = NULL;
276 }
277
278 return true;
279}
280
281static void bio_end_empty_barrier(struct bio *bio, int err)
282{
283 if (err) {
284 if (err == -EOPNOTSUPP)
285 set_bit(BIO_EOPNOTSUPP, &bio->bi_flags);
286 clear_bit(BIO_UPTODATE, &bio->bi_flags);
287 }
288
289 complete(bio->bi_private);
290}
291
292
293
294
295
296
297
298
299
300
301
302int blkdev_issue_flush(struct block_device *bdev, sector_t *error_sector)
303{
304 DECLARE_COMPLETION_ONSTACK(wait);
305 struct request_queue *q;
306 struct bio *bio;
307 int ret;
308
309 if (bdev->bd_disk == NULL)
310 return -ENXIO;
311
312 q = bdev_get_queue(bdev);
313 if (!q)
314 return -ENXIO;
315
316 bio = bio_alloc(GFP_KERNEL, 0);
317 bio->bi_end_io = bio_end_empty_barrier;
318 bio->bi_private = &wait;
319 bio->bi_bdev = bdev;
320 submit_bio(WRITE_BARRIER, bio);
321
322 wait_for_completion(&wait);
323
324
325
326
327
328
329 if (error_sector)
330 *error_sector = bio->bi_sector;
331
332 ret = 0;
333 if (bio_flagged(bio, BIO_EOPNOTSUPP))
334 ret = -EOPNOTSUPP;
335 else if (!bio_flagged(bio, BIO_UPTODATE))
336 ret = -EIO;
337
338 bio_put(bio);
339 return ret;
340}
341EXPORT_SYMBOL(blkdev_issue_flush);
342
343static void blkdev_discard_end_io(struct bio *bio, int err)
344{
345 if (err) {
346 if (err == -EOPNOTSUPP)
347 set_bit(BIO_EOPNOTSUPP, &bio->bi_flags);
348 clear_bit(BIO_UPTODATE, &bio->bi_flags);
349 }
350
351 if (bio->bi_private)
352 complete(bio->bi_private);
353 __free_page(bio_page(bio));
354
355 bio_put(bio);
356}
357
358
359
360
361
362
363
364
365
366
367
368
369int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
370 sector_t nr_sects, gfp_t gfp_mask, int flags)
371{
372 DECLARE_COMPLETION_ONSTACK(wait);
373 struct request_queue *q = bdev_get_queue(bdev);
374 int type = flags & DISCARD_FL_BARRIER ?
375 DISCARD_BARRIER : DISCARD_NOBARRIER;
376 struct bio *bio;
377 struct page *page;
378 int ret = 0;
379
380 if (!q)
381 return -ENXIO;
382
383 if (!blk_queue_discard(q))
384 return -EOPNOTSUPP;
385
386 while (nr_sects && !ret) {
387 unsigned int sector_size = q->limits.logical_block_size;
388 unsigned int max_discard_sectors =
389 min(q->limits.max_discard_sectors, UINT_MAX >> 9);
390
391 bio = bio_alloc(gfp_mask, 1);
392 if (!bio)
393 goto out;
394 bio->bi_sector = sector;
395 bio->bi_end_io = blkdev_discard_end_io;
396 bio->bi_bdev = bdev;
397 if (flags & DISCARD_FL_WAIT)
398 bio->bi_private = &wait;
399
400
401
402
403
404
405 page = alloc_page(GFP_KERNEL | __GFP_ZERO);
406 if (!page)
407 goto out_free_bio;
408 if (bio_add_pc_page(q, bio, page, sector_size, 0) < sector_size)
409 goto out_free_page;
410
411
412
413
414
415
416 if (nr_sects > max_discard_sectors) {
417 bio->bi_size = max_discard_sectors << 9;
418 nr_sects -= max_discard_sectors;
419 sector += max_discard_sectors;
420 } else {
421 bio->bi_size = nr_sects << 9;
422 nr_sects = 0;
423 }
424
425 bio_get(bio);
426 submit_bio(type, bio);
427
428 if (flags & DISCARD_FL_WAIT)
429 wait_for_completion(&wait);
430
431 if (bio_flagged(bio, BIO_EOPNOTSUPP))
432 ret = -EOPNOTSUPP;
433 else if (!bio_flagged(bio, BIO_UPTODATE))
434 ret = -EIO;
435 bio_put(bio);
436 }
437 return ret;
438out_free_page:
439 __free_page(page);
440out_free_bio:
441 bio_put(bio);
442out:
443 return -ENOMEM;
444}
445EXPORT_SYMBOL(blkdev_issue_discard);
446